<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
	</body>
	<script type="text/javascript">
		let p1 = new Promise((resolve, reject)=>{
			setTimeout(()=>{
				resolve('成功')
			}, 1500)
		})
		.then(null, err=>{})
		
		new Promise((resolve, reject)=>{
			// 这里响应的是p1这个promise对象
			// 当p1响应之后，这个promise才会执行
			resolve(p1)
		})
		.then(res => {
			console.log(res)
		}, err=>{})
	</script>
</html>
